In recent years, the interaction of neighborhood characteristics and children's well-being has become a topic of considerable debate both in the academic and public policy communities. Research to date has been seriously hampered by a lack of data adequate to address the complex set of associations between neighborhood characteristics, family life, family choices about geographic mobility and children's well-being. We propose to carry out the Los Angeles Study of Families and Communities (LASFC), a longitudinal survey of children, their families, and their neighborhoods in 65 neighborhoods in Los Angeles County, over a four year period. Poor neighborhoods and households with children will be oversampled. The LASFC will collect extensive information on family social and economic status and background, labor force participation, family dynamics and parenting, social ties, geographic mobility, neighborhood attitudes and involvement, and family use of publicly-and privately-funded child-related services. A unique feature of the LASFC is that we propose both to follow households which move out of sampled neighborhoods and to interview a new sample of households which have moved into the neighborhood in the year preceding each wave of the survey. The LASFC data will be placed into the public domain after each annual wave as quickly as possible, to enable a wide range of investigators to carry out research.